During joining of non-round, asymmetrical functional components, in particular during thermal joining of cams (pump cams or valve actuation cams) to camshafts, deformation of the tube, that is, the shaft can occur in the region of the functional components, that is, in the region of the cams, owing to the transverse press fit and the associated overlap between the cam bore and the camshaft tube diameter. In the case of bearing points which are arranged adjacently to the functional components, this can result in deviations from the round shape, which lie outside specifications for good bearing. In such cases, the bearing points may have to be subsequently ground after the functional components have been joined, which however represents an additional manufacturing step, since the shaft has already been ground previously. The additional manufacturing step is not only complex and time-intensive, but also expensive.